A synchronizer assembly for a vehicle transmission, where the synchronizer assembly is electrically actuated during a shift. The assembly includes a sleeve having an inner surface and an outer surface. A rotor is rotatably mounted to the outer surface of the sleeve and a shift collar is axially mounted to the inner surface of the sleeve. The rotor is threadably coupled to the shift collar so that when the rotor rotates, the shift collar moves in an axial direction relative to the sleeve. An armature coil is electrically coupled to the rotor to cause it to rotate. Keys are rigidly secured to the shift collar to maintain the orientation of the shift collar while it moves. The shift collar locks a shift gear to the transmission output shaft during a shift.